The statement said Ms Powell would visit Washington soon for consultations on US-Nepal relations.

'Words and actions'

The US embassy statement said that Ms Powell and Prachanda, whose real name is Pushpa Kamal Dahal, discussed the outcome of last month's elections to a constituent assembly.

It said Ms Powell encouraged the Maoist leader to ensure that the former rebels showed their commitment to the political process through their words and actions.

The Maoists were the biggest single party in recent elections, winning 220 out of 601 seats.

They are committed to abolishing the monarchy and have urged King Gyanendra to leave office voluntarily.

Prachanda has said that he wants to be president.

The Maoists now have to forge a coalition interim administration to draw up a new constitution.

'Embarrassing'

For the past year the US has tried to bypass the Maoists while dealing with an interim government of which they were members.

Speaking just after the 10 April elections, former US President Jimmy Carter told the BBC he found America's failure to deal with the Maoists "embarrassing".

During 10 years of insurgency which left thousands dead, both the Maoists and the military were accused of gross human rights abuses.

Analysts say there are many problems facing the Maoists.

The other main parties do not trust them.

Since the elections, Prachanda has promised that the Maoists are committed to multi-party and peaceful politics.

However its members, particularly in its youth wing, have been accused of intimidation and extortion.

The army is also opposed to the Maoists' demand that its former fighters be integrated into the armed forces.

The long insurgency has worsened the chronic poverty in Nepal which, like other countries in the region, is suffering from rising food prices.

The Maoists signed a peace accord with Nepal's main political parties in 2006. The year before the increasingly unpopular King Gyanendra had been forced to restore parliament amid a wave of street protests.